import matplotlib.pyplot as plt

plt.plot([7,8,9,10,11,12,13,14,15,16,17,18],[10,10,10,30,20,25,30,35,70,75,80,10])
v= [7,18,0,100]
plt.axis(v)
plt.grid(True)
plt.title('processorbelasting')
plt.xlabel('Tijdstip in uur')
plt.ylabel('Gemiddeld percentage per uur')
plt.legend(["processorbelasting gemeten over 12 uren"], loc=2)
plt.annotate('Wat gebeurt hier!', xy=(17, 80), xytext=(16, 90),
            arrowprops=dict(facecolor='black', shrink=0.05),
            )


plt.show()
